Integration of caveolin-mediated cytosolic delivery and enzyme-responsive releasing of squalenoyl nanoparticles enhance the anti-cancer efficacy of chidamide in pancreatic cancer

We explored the potential of overcoming the dense interstitial barrier in pancreatic cancer treatment by enhancing the uptake of hydrophilic chemotherapeutic drugs. In this study, we synthesized the squalenoyl-chidamide prodrug (SQ-CHI), linking lipophilic squalene (SQ) with the hydrophilic antitumor drug chidamide (CHI) through a trypsin-responsive bond. Self-assembled nanoparticles with sigma receptor-bound aminoethyl anisamide (AEAA) modification, forming AEAA-PEG-SQ-CHI NPs (A-C NPs, size 116.6 ± 0.4 nm), and reference nanoparticles without AEAA modification, forming mPEG-SQ-CHI NPs (M-C NPs, size 88.3 ± 0.3 nm), were prepared. A-C NPs exhibited significantly higher in vitro CHI release (74.7 %) in 0.5 % trypsin medium compared to release (20.2 %) in medium without trypsin. In vitro cell uptake assays revealed 3.6 and 2.3times higher permeation of A-C NPs into tumorspheres of PSN-1/HPSC or CFPAC-1/HPSC, respectively, compared to M-C NPs. Following intraperitoneal administration to subcutaneous tumor-bearing nude mice, the A-C NPs group demonstrated significant anti-pancreatic cancer efficacy, inducing cancer cell apoptosis and inhibiting proliferation in vivo. Mechanistic studies revealed that AEAA surface modification on nanoparticles promoted intracellular uptake through caveolin-mediated endocytosis. This nanoparticle system presents a novel therapeutic approach for pancreatic cancer treatment, offering a delivery strategy to enhance efficacy through improved tumor permeation, trypsin-responsive drug release, and specific cell surface receptor-mediated intracellular uptake.

Selective inhibition of tumor microvascular permeability by cavtratin blocks tumor progression in mice

Tumor vasculature is hyperpermeable to macromolecules compared to normal vasculature; however, the relationship between tumor hyperpermeability and tumor progression is poorly understood. Here we show that a cell-permeable peptide derived from caveolin-1, termed cavtratin, reduces microvascular hyperpermeability and delays tumor progression in mice. These antipermeability and antitumor actions of cavtratin occur in the absence of direct cytostatic or antiangiogenic effects. Cavtratin blocks microvascular permeability by inhibiting endothelial nitric oxide synthase (eNOS), as the antipermeability and antitumor actions of cavtratin are markedly diminished in eNOS knockout mice. Our results support the concepts that hyperpermeability of tumor blood vessels contributes to tumor progression and that blockade of eNOS may be exploited as a novel target for antitumor therapy.